1. Field of the Invention
The present invention pertains primarily to metallic coating compositions for use on roofs, walls and the like, and more particularly to metallic coating compositions containing asphalt and aluminum.
2. Description of the Prior Art
The state of the art is believed to be indicated by the following references:
______________________________________ U.S. Pat. No. Inventor Issued ______________________________________ 1,765,676 Jones June, 1930 2,068,966 Thurston et al January 26, 1937 2,461,352 Smith et al February 8, 1949 2,858,230 Knoll et al October 28, 1958 3,244,542 Brown et al April 5, 1966 3,291,011 Defregger et al December 13, 1966 3,869,297 Bellomy March 4, 1975 ______________________________________
Generally, asphaltic roof coating materials have been widely used from many years as weather-proofing coatings to seal roofs and prevent the entry of water into the underlying structure. By the addition of metallic particles such as aluminum, such roof coating materials can also be made to exhibit desirable heat reflective properties and thus help maintain the underlying structure at temperatures considerably below those of the exterior ambient air.
Typical asphaltic roof coating materials are comprised of a clay base which contains clay, water and asphalt; aluminum paste, which is aluminum powder or flakes ground in oil; asbestos fiber; non-fibrous fillers, such as limestone or mica; and other additives designed to enhance mixing, adjust viscosity and/or prevent corrosion. Water is normally used in the clay base since it is readily available and economical. However, it is well-known that aluminum particles oxidize in the presence of water in a relatively short time, thus destroying the usefulness of the aluminum particles because of loss of luster, gloss, brilliance and color due to the formation of dull-surfaced aluminum hydroxide, as well as forming hydrogen gas which develops considerable pressure inside of sealed containers.
Many of the prior art attempts to solve the above problems have proven only marginally successful. For example, the aluminum particles may be coated with a corrosion preventing material, but this procedure adds substantial cost to the roof coating material. Another solution has been to mix the water and aluminum-coating components together just prior to application, so that very little opportunity is provided for reaction, however, this procedure significantly complicates the application procedure beyond that tolerable by most roofing contractors.
Most prior art formulations, which are based upon either industry or government specifications and which have attempted to solve the above problems, contain asbestos, which has recently become rather difficult to obtain due to material scarcity and costs, as well as posing possible serious health problems. In the past, it has been difficult to eliminate asbestos as a filler material and still obtain a functional product.
It is accordingly a principal object of the present invention to provide a new and improved asphalt-aluminum coating composition.
It is another object of the present invention to provide an asphalt-aluminum coating composition containing no asbestos fiber, which exhibits superior reflectivity, but which contains less aluminum than typical asbestos-containing compositions.
It is another object of the present invention to provide a coating composition containing no separate water component.
Other objects, features and advantages of the present invention will become apparent from the subsequent description, examples and the appended claims.